(1) Field of the Invention
The invention relates to a modular, expandable measuring device that includes an access-protected area and, more particularly, to an energy counter with tamper detection and communication interfaces.
(2) Description of Related Art
Nowadays consumption data is recorded on various utility supplies in a household (electric energy, cold water, hot water, air-conditioning, gas, fuel, and other materials of the kind), the meters being located in various measurement points. In all their applications all these utility services, which are collectively called Multi Utility, share the following characteristics:                The need that values that are taken and checked (calibrated) and shown in the invoice should be beyond doubt (in a word, consumer protection);        Values taken locally should be digitized and transferred to a central office to be processed;        The implementation of a fast, timely and customer oriented book-keeping should be conducted as well as Cash Management control; and,        The need to create a uniform solution for all kinds of supplying.        
Prior technical development of measurement devices and systems for taking combined seizing/reading of consumption data have certain typical weakness and problems such as lack of general validity or single solutions in regard to certain segments. Usually, utility companies like power supply companies or water supply companies prepare consumption reports based on data based on data of customers' counting devices, which most often are installed close to the consumption point. The measurement devices may be for gas, water, electricity, heating, etc., and data provided by them covers previous periods, showing consumption in the relevant consumption point. In principle, data reporting of the counter and, respectively, data reading is made at least once a year for every house, apartment or a consumption point.
Electric meters featuring two or more counters to calculate different rates, whose counters are reset through built-in or external remote control receivers (that are controlled via a central remote control equipment on the premises of energy suppliers) or are switched over through automatic timers, respectively, are utilized for long periods of time. The electronic electric meters developed in the past few years do not contain mechanical elements. For example, energy consumption is measured through a current transformer with a soft-magnetic ring core (respectively, a measurement system with Rogowski coil) with the help of a shunt resistor (Shunt) or a hall element. Energy metering is made through an electronic device, while the result is reported on an alpha-numerical display (most often a liquid crystal display, LCD). Some special (industrial) customers use a different type of counters, as they measure power. In reality, however, counters here are gradually being replaced by electronic ones, reporting the loading, for measuring the active and reactive power (load profile meter). In this way, the rate setting can be changed without contacting the counter; therefore, there is no more need for separate/individual counters in the electric meters.
Readings of some electronic electric meters can be taken remotely from the energy and automation suppliers through the interface. In practice, the interface used represents: an infrared port, S0-interface, M-Bus, potential-free contact e.g. connected to GSM, PSTN modems or PLC modules. At present (April, 2006), in Germany field tests are conducted via an uninterrupted internet connection (DSL). In the United States, electronic electric meters for households are being developed with built-in relays, which, for example, allow them to cut electricity off until the electricity bill is paid, in addition to remote readings taking. In Germany, in the frame from pilot projects intelligent counters become increased usage to introduce Smart Metering technology. Usually, impulse-outputs (S0) are sending consumption-related signals, between 2000 to 5000 impulses per kW/h. Afterwards, depending on the counter, this value should be multiplied by a certain coefficient, for example, 30 or 50, to get the cumulative value.
In the Federal Republic of Germany, electric meters used in trade are subject to calibration duty. Once the calibration term of validity expires (in 16 years, 8 years for electronic electric meters, in 12 years for mechanical induction electric meters i.e. with a rotor disk, respectively), the measurement device should be changed or the term of validity extended.
For example, from WO 2006/048143 A1 a device is known which is able in a reliable and energy-saving way to detect manipulations on the housing of household electric meters without using mechanically triggered buttons or magnetic and photoelectric switches. In particular, this device envelops a part of the body where the electronic receiver is placed, as well as a second, separate from the first, part of the body, with the first part being secured against illegal removal of the second part. An electrical resonant circuit is envisaged in the first part of the body, and this circuit is made of spool and a capacitor, while the spool emits signal through the metal element placed in the second part of the body when the distance between the spool and the metal element changes. This signal is directed to the electronic plate in the first part of the body and assists further processing. In order to find that the second part of the body is parted from the first one, which determines the change of quality of the spool within the resonant circuit, absorption power of the oscillation of the resonant circuit decreases along with the continuation of the electric switch's reverse pulse. The device's electric resonant circuit is mounted close to a low energy consuming interrupt. A very short, low energy, voltage pulse is enough to feed this resonant circuit. If the excitation occurs concurrently at a relatively low frequency, e.g. once every 10 seconds, a low average power of the control circuit is achieved, allowing a device featuring primary or secondary batteries or high capacity capacitors to run for a very long period. The continuation of the reverse impulse is directly related to the absorption power of the oscillations of the resonant circuit and is calculated using a microprocessor circuit.
Such a protection against unauthorized manipulation is known from WO 2004/021020 A1. It applies to a counter body with a sealed cap that covers counter terminals, where at least one of the additional devices is covered, i.e. is secured against unauthorized access through a second seal. The seal of the second measuring device that needs protection is designed in a manner that is freely accessible when there is no cap to the terminal box, enabling easy and fast inspection. Therefore, the body of the electric meter is equipped with at least one hoop on the seal, connecting the hole for the seal to the additional cover, with the seal's locking-finger functioning as a connecting element of at least one hoop and one hole. It is very advantageous when at least one hoop is placed at a distance from the hole for the seal, so that the breaking point of the locking-finger is visible, especially in the case of transparent locking-fingers.
Also, adapters or carrying panels for electronic home meter (shortly, eHZ) are known, on their fixing sides are arranged external terminals protruded down which are connected with suitable contact appliances. In this manner, a change of electric meter or new mounting can be implemented, and it will not be necessary for the user's power supply to be interrupted. As a rule, these platforms are present in positions of delivery, mounting or operation. Users can try to change, even for a while, the platform from operation position to a installation position so that the electric current consumed by them not to be read by the counter. Also, consumers whose electric meter has been taken down and the platform has changed into a position of delivery, can try to change the platform from position of delivery to mounting position in order to consume electric current from the network in an unauthorized manner without paying for it. In order to prevent in practice unauthorized usage of electric energy even with removed sealing appliance between the counter and the platform, according to DE 10 2006 055 322 A1 a system is known for energy meter with circuit-interrupt mechanism and receiving platform with a device for detecting when moving. In this case the circuit-interrupt mechanism interacts with the device for detecting when moving in such a manner that when moving the counter over the platform from an operation position into a position of installation, the circuit-interrupt mechanism interrupts permanently the power supply to the energy meter. The circuit-breaking mechanism can be equipped, for instance, with a disconnecting circuit-interrupt with switching lever for its manually switching on and off, as well as with a block system that is arranged in such a manner that when released, the disconnecting circuit-interrupt is opened (main emergency circuit-interrupt, line protecting circuit-interrupt) and its closing by the switching lever is not possible. Alternatively, the mechanism for circuit-interrupt can be equipped with a mechanism for disconnecting by force (a mechanism for operating current switching off, accessory driving mechanism) which through a device for detecting when moving can be changed from a position of switching on into a position of switching off and which interacts with the blocking system of the disconnecting circuit-interrupt in such a way that it is unblocked in a position of switching off the mechanism for disconnecting by force. The interrupt of power supply can be achieved only through a special restarting device. Besides, the device for detecting when moving comprises a terminal switch or photoelectric switch (energy meter clamping braces) that are connected or are driven in such a manner that a recognition signal for moving to be sent to the circuit-interrupt mechanism in case that the energy meter is changed from operation position into a position of installation. Furthermore, the device for detection when moving comprises a delay device (delaying the recognition signal when moved for a few minutes) so the technician shall have enough time to replace the energy meter without interrupting the power supply by the main emergency circuit-interrupt. And finally, the recognition signal when moving can be transferred through a remote device to the mechanism for interrupting from and to remote places. For this purpose, as a remote device a modem connection via a telephone line can be used.
In order to make possible an unambiguous, automatic and faultless attachment to the respective place for recording and data reading when using carrying panels (installation elements, installation facilities) and the recording and data reading changeable device, fixed on them, from DE 10 2007 021 138 A1 a recording device is known with at least an electronic fuse or with a seal. In particular, the installation element comprises at least one information device with permanent memory for storing the identified information and/or data from the installation element and/or place where the information is recorded. The recording device comprises at least a device for these data reading. It is preferable that the information device is formed as a RFID-TAG, which is implemented in such a manner that when opening the access-protected area, unpreventable destruction of the seal occurs, i.e. destruction of one of the essential functional elements of this information device. This state is recorded by the reading device, is stored in the recording device and/or data transfer to the central controlling or data recording block is implemented. By the way, the recording devices are sensors or controlling devices of a control system but mainly they are counting devices and in particular, energy consumption counting devices. Inside the housing of the counting device there is at least one access-protected area. The housing can be opened by authorized persons, consists of two parts, connected with each other. For sealing, respectively safeguarding the internal housing area, on its external side at least one electronic seal has to be placed and it has to cover the transition between these two parts. The protection removal from the housing and/or opening the housing is not possible without destroying one of the essential functional elements of the electronic protection, for example destroying the antenna structure and/or integrated board for switching RFID-TAG. This fact also can be transferred immediately to the central controlling or data recording block. RFID-TAG can be arranged in a partition of the installation element—for example built-in or cast—or can be arranged at or in a housing partition.
To reduce the numbers of variants of the recording device, from DE 20 2004 002 731 U1 an adapter is known to the energy meter with at least one integrated measuring current and voltage transformer. Each measuring current and voltage transformer is constructed in such a way that to be suitable for connecting on the one part, to a measuring transformer in the user's connection point to the network, and on the other hand, to an energy meter. The secondary current of the measuring current transformer (second transformer) runs in the energy meter, respectively in the electric current sensor of the energy meter (this current can be referred to as tertiary current). The tertiary current can be measured through the ratio of the coil number in the transformer so, that the measuring transformer primary current to be equal to the tertiary. In this manner an electronic home energy meter can be installed whose functional range is equal to the conventional, directly connected transformer for industrial appliances. In this way, it is preferably that an energy meter to be placed, the best of all with an option to record transmission load for active and reactive energy measurement (load profile meter) that is designed for direct connection to the power supply line in the connection point, respectively is specified as an eHZ-technology. If an energy meter has to be replaced, it can be taken down in the same manner as it is switched off and the new one to be connected easily in the same manner.
Furthermore, from DE 10 2005 061 216 A1 a consumption counter is known, more precisely a consumption reporting device for heating, water or gas which comprises a main device and a separate module for data transfer to and from the main device. In particular, to the individual number of the main device a freely chosen by the user user's name can be added and under this name the data from the main device and the separate module can be read. This means that after replacement of the main device, for example because of the calibration term of validity expires, no changes for reading the consumption must be undertaken. For the main device and separate module a record for data replacement is drawn up where in a completely automatic way the same name and data are set and where the data transfer between the main device and separate module is bi-directional. The same applies when the module replacement has to be done with more advanced because of the increased requirements. Besides, the module comprises a connection for external bus, more particular M-bus that can be connected wireless or via a cable. In this case the module interface to the main device is identical with the wireless connection interface and this makes the module switching on “transparent”, i.e. an external block can access directly the main device, e.g. in case of technical servicing, new programming, etc. In case that a heat counting device is present, a metering block reports the consumption and this is based on the measured values entered to the sensors. In this case the correcting values stored in the memory serve for the precise main device count to be obtained. The metering and storing block are supplied by a battery whose capacity should be great enough to supply the main device during the whole five-year period of calibration validity. The main device comprises all the components needed for calibration and a data interface, eventually an energy interface, e.g. by an induction coil or connected through a capacitive board or via a cable, for example also an interrupt-generator.
Furthermore, from US 2006/0091877 A1 a device is known for electric energy reading with a microprocessor core which comprises also the function of tamper detection. The tamper detection is based on a tamper sensor usually it is a switch (opening detector). Therefore, in case with US 2006/0091877 A1, certain means are always required, namely sensor, switch, impedance detection board, etc. and in the last case also additional protection for variable peaks of over-voltage (through resistors and diodes). As external modules only a service module is stated, e.g. portable reading device, wirelessly connected to the energy counter, (optional) external memory (with expanded options) and a relay for external device switching on.
And finally, from U.S. Pat. No. 4,571,691 a device is known for valuable energy measuring, where the tamper detection is implemented through control over a separate transmission line, where upon removing the bolts or when removing, respectively moving the fixing ring (e.g. which is needed for housing cap removal), irreversible switching off occurs. In this case the disadvantages are that it requires, firstly: a separate transmission line (e.g. optical fibres) and secondly: specific installation of this line that increases expenses during the implementation.
That is, from the technical point of view different systems are known for tamper detection on the part of the end user/customer, in particular, through sealing the housing cap (e.g. WO 2004/021020 A1) or electronic seal (electric resonant circuit as per WO 2006/048143 A1 or RFID as per DE 10 2007 021 138 A1). In principle, the devices of power supply companies are equipped in such a way that the consumption data from the consumption point (i.e. end user, e.g. in the household but also in the industry and public sector) are reported as easily as possible and at advantageous rates (resource counters, e.g. energy meters and water meters) and are transferred to the power-station in the easiest possible way and at advantageous rates as well (communication methods) where they are processed through automatic reading for the said end users. The user is always the operator, competent to do the measurement, respectively the person doing the measurement service who deals with the delivery of the counter for the relevant resource measuring, installs it for the customer, maintains and reads it; the same applies also to the communicational devices. Lacking in practice, however, is a measuring device/meter which can be used universally, independently of other technical conditions, and which can be expanded/adapted in a simple manner and has at least one access-protected area/space in the housing. This is particularly significant because the industry that produces measurement devices has been regarded as an extremely advanced, development-oriented industry which rapidly takes up and actually implements improvements and simplifications.